HK1191606A - Method and system for manufacturing railcar coupler locks - Google Patents

Description

Method and system for manufacturing railcar coupler locks

Background

Railway car couplers are used to couple railway cars together. Typical couplers commonly used in north america are either E-type or F-type couplers. These couplers incorporate a lock that interacts with the knuckle of the coupler to lock the knuckle into a closed position. Typically, the lock is adapted to fit within the lock cavity of the knuckle body and over the knuckle tail. The lock has a width sized to slide within the lock cavity.

Locks used in such couplers are typically made by casting. The most common technique for manufacturing locks is by sand casting. The complex shapes manufactured by sand casting are low in cost and high in yield. In a typical sand casting process, a mold is constructed by filling a pattern with molding sand, generally defining a casting system through which molten metal flows. The mold is then removed from the mold to form a cavity in the shape of the cast article, corresponding to the final casting. A core defining an internal cavity and a channel is placed within the mold. The mould is then closed and filled with hot liquid metal through the down-runner, where the metal cools. The solidified metal or the rough casting is removed by separating the mold. The casting is then separated from the gate, finished and cleaned by grinding, welding, heat treating and machining.

In the sand casting process, a mold is constructed using sand as a base material mixed with a binder to maintain the shape. The mold is built in two parts, called a cope part (e.g., the top half) and a drag part (e.g., the bottom half), which are separated along a flat parting line. A draft angle of up to 3 degrees or more is machined into the pattern to ensure that the pattern is released from the mold upon removal. In some sand casting operations, an exterior sand box is used to support the sand during the molding process through the pour method.

After the metal is poured into the mold, the casting cools and shrinks as it approaches a solid state. As the metal shrinks, additional liquid metal must continue to be injected into the area of the shrinkage or voids will appear in the final part. In the high shrinkage region, risers are formed in the mold to provide additional storage during casting. These risers are the last to solidify, thus allowing the contents to remain liquid longer than the cavity of the part being cast. As the contents of the mould cavity cool, the risers feed into the constricted region, ensuring that a solid final casting is produced. The risers that are open at the top of the cope mold may also act as vents for venting gases during pouring and cooling.

In various casting techniques, different sand binders are used to hold the sand in the shape of the pattern. These binders have a great impact on the final product as they control dimensional stability, surface finish, and the realization of casting details in each particular run. Two of the most typical sand casting methods include (1) green sand, which consists of silica sand with clay and water as binders; and (2) a chemical or resinous binder material composed of silica sand and a fast curing chemical binder system such as phenolic urethane. Traditionally, locks are constructed using the green sand process, which is inexpensive because of the cost associated with the molding material.

Although green sand has been effective in making locks for many years, this process has some drawbacks. For example, the surface of the lock is polished rough, and the thickness of the locking surface of the lock varies. These asperity defects and variations must be addressed by grinding and other finishing to ensure that the final lock meets dimensional requirements. Other problems with these casting processes will become apparent upon reading the following description.

Disclosure of Invention

It is an object of the present invention to provide a method of manufacturing a lock for a railcar coupler that substantially eliminates surface imperfections and dimensional differences. The method includes forming a mold of the lock in a drag portion and a cope portion of a first mold containing a first molding material to define a cavity defining an outer surface of the lock. A mold cavity is formed in a second mold having a second molding material. The cavity defines an interior surface that is substantially complementary to an exterior surface of the first mold. A down-gate, a gating system in fluid communication with the down-gate, a riser in fluid communication with the gating system, and a gate in fluid communication with the gating system and the first mold are formed in the second mold. The first and second molds are solidified. The first mold is assembled and inserted into the cope portion of the second mold. The second mold is assembled and the melt is poured into the down sprue of the second mold. The melt then flows into the first mold to form the lock.

A second object of the present invention is to provide a method of manufacturing a lock of a railcar coupler, including forming a mold of the lock in a drag portion and a cope portion of a first mold, the first mold including a first molding material to form a cavity defining an outer surface of the lock. The cope portion defines a first opening configured to exhaust gas. A cavity having an interior surface substantially complementary to the exterior surface of the first mold is formed in a second mold comprising a second molding material. A first opening configured to vent gas from the first opening of the cope portion of the first mold is formed in the cope portion of the second mold. The down runner, a gating system in fluid communication with the down runner, and a gate in fluid communication with the gating system and the first mold are formed from a second molding material. The first mold and the second mold harden. The first mold is assembled and inserted into the cope portion of the second mold. The second mold is assembled and the melt is injected into the down sprue of the second mold. The melt then flows into the first mold to form the lock. The gas in the first mold is extruded by the melt through the first opening in the cope portion of the first mold, and then through the first opening in the cope portion of the second mold.

A third object of the present invention is to provide a method of manufacturing a lock of a railcar coupler, including forming a pattern of at least two locks in a drag portion and a cope portion of a mold, the mold including a naturally hardened molding material, thereby forming a cavity defining outer surfaces of the at least two locks. The down runner, a gating system in fluid communication with the down runner, and at least two gates each in fluid communication with the gating system and one of the at least two cavities are formed from a naturally hardened molding material. The natural hardening molding material is hardened. The drag and cope portions of the mold are combined. The melt is injected into the down sprue of the hardened naturally hardened molding material, wherein the melt then flows through the gating system and into the mold cavity, thereby forming the at least two locks.

It is a fourth object of the present invention to provide a casting assembly for manufacturing a lock of a railcar coupler. The casting assembly includes a drag portion and a cope portion of a first mold that define an outer surface of a lock. The first mold includes a first molding material. The casting assembly further includes a second mold made of a second molding material. The second mold defines a cavity having an interior surface that is substantially complementary to the exterior surface of the first mold. A down-gate is formed in the second mold. A gating system is formed in the second mold and is in fluid communication with the down sprue. A gate is formed in the second mold and is in fluid communication with the gating system and the first mold.

Other features and effects will become apparent to one with skill in the art upon examination of the following figures and detailed description. All additional features and effects contained in the present description should be within the scope of protection of the claims and protected by the following claims.

Drawings

The accompanying drawings are included to provide a further understanding of the claims, and are incorporated in and constitute a part of this specification. The details of the description and the illustrated embodiments are set forth to explain the principles defined by the claims.

FIG. 1 illustrates a perspective view of a lock within the body of a railcar coupler;

figures 2a and 2b illustrate a perspective view and a side view, respectively, of the lock shown in figure 1;

figure 3 illustrates an overmold assembly that may be used to form the lock shown in figures 2a and 2 b;

figures 4a and 4b illustrate the interiors of the cope and drag portions, respectively, of the cope mould shown in figure 3;

FIG. 5 illustrates an interior view of the outer mold after the melt is poured;

FIG. 6a illustrates a side view of the shell;

FIG. 6b illustrates the cope and drag portions of the shell mold shown in FIG. 6 a;

FIG. 7a illustrates another view of the drag portion of the shell mold;

FIG. 7b illustrates a cross-sectional view of the drag portion taken along section A-A' in FIG. 7 b;

FIG. 8 illustrates the drag portion cavity with respect to the lock;

figure 9 illustrates a process for manufacturing the lock of figure 2 a.

Detailed Description

The following examples describe methods for making multiple locks in a single casting operation. Typically formed as a set of shells defining the shape of the lock. The shell mold is a mold made of fine silica sand mixed with thermosetting phenol resin and relatively expensive. The fine silica sand allows the lock to have a smooth surface finish and relatively high dimensional accuracy relative to locks manufactured by other casting processes.

However, current shell mold production techniques optimize existing size shell molds and result in relatively small shell molds. The larger shell machines that exist tend to be very expensive. Increasing the size of the shell to withstand the large discharge pressures required would be very expensive when technically feasible. Thus, the shell mold is placed into an outer mold. The outer mould is made of a relatively low cost, naturally-hardening or self-hardening sand moulding material and is arranged to receive the shell mould. In the depicted embodiment, the overmold is configured to receive four shell molds.

A gating system formed in the overmold is configured to distribute melt poured into the mold through a down-runner to each shell mold. Vents in the shell allow air and other gases to escape as the melt fills the shell. The vent openings are generally aligned with vent openings in the overmold to allow the gas to vent to atmosphere.

Figure 1 illustrates a perspective view of a lock 105 within a body 100 of a railcar coupler. Fig. 2a and 2b illustrate a perspective view and a side view, respectively, of the lock 105 shown in fig. 1. The lock 105 includes a rear leading end 205, a mid-section pillar portion 210, and a knuckle side end 215. The knuckle side end 215 defines a recess 220. Near the rear leading end 205, the lock 105 defines a knuckle locking face 225 and a coupler locking face 230.

Running lock 105 requires sliding the lock 105 within the lock cavity of the knuckle body and over the knuckle tail. In order for the lock 105 to operate smoothly, the knuckle lock face 225 and the coupler lock face 230 must be substantially parallel and smooth to each other. In addition, the distance D207 between these two faces of the different locks must be precise and consistent. The distance D207 of the locks 105 made by the disclosed casting process is about 3.060 inches and the difference between the different locks is less than about ± 0.010 inches. These dimensions can be achieved by the claimed casting process plus locked minimal machining. Locks produced by known manufacturing processes must be machined to produce a smooth surface machined by sandblasting or other methods. A relatively fine casting of the vent holes may be forged leaving a relatively small area for grinding. Similarly, a cast connector 505 (FIG. 5) connects the lock 105 to a detachable casting runner system from the end surface 207 of the rear lead end 205. In some cases, the residual casting of the connection 505 may not require further grinding because the end surface 207 is not typically a critical surface.

Fig. 3 illustrates a closed overmold assembly 300 that may be used to form the lock 105 described above. The overmold 300 includes a cope portion 305 and a drag portion 307. Cope and drag portions 305 and 307 are made of a molding material, such as self-hardening sand or self-drying sand. The down sprue 320 is placed in an opening of the cope through which molten metal is injected. The cope portion 305 defines first and second sets of exhaust openings 325 and 330 for exhausting gases generated during a casting process within a cavity formed in and defined by the overmold 300. An air vent opening 335 may also be provided in one side of the drag box portion 307.

The molding material used in the overmold 300 is a relatively lower cost and stronger molding material that is generally not capable of forming locks that meet the required surface finish and dimensional accuracy details. For example, the grit fineness index (GFN) of the modeling material may be in the range of 44-55 grit fineness indices.

In some embodiments, the molding material is reclaimed sand (i.e., sand that has previously been used to make castings). Reclaimed sand can be obtained by subjecting used molds to various vibration and/or crushing procedures that break down the molds and classify the sand into finer and finer component sizes until the desired grain size is achieved. The screening process helps to separate the sand by size. Finally, the sand is subjected to high temperatures to eliminate any residual covering or other impurities, such as binder materials. The reclaimed sand is then mixed with fresh binder at a ratio of about 99:1 and placed into a mold to harden. Once hardened, the new mold is ready to receive the melt.

In some embodiments, two or more levels of modeling material are used to form the overmold 300. For example, the outer layer 310 of the mold (i.e., defining the exterior of the outer mold) may be made of a low grit. The low-grade material is not subjected to the various separation procedures described above. For example, hot working may not be performed in order to save time. In addition, a smaller amount of adhesive material may be used to bond the less refined material. For example, the sand to binder ratio may be greater than 99: 1.

The inner layer 315 of the mold may be made of high-precision sand that is reclaimed by the separation process described above. The use of different grades of recycled material generally reduces the manufacturing costs associated with the outer mold 300 due to the need for low grit. High grit is retained only for those portions of the outer mold 300 that require greater dimensional accuracy or a higher surface finish.

Fig. 4a and 4b illustrate the interior of the cope portion 305 and the drag portion 307, respectively, of the outer mould 300. In fig. 4b, the shell 400 is also shown disposed within the drag portion 307. The overmold 300 is configured to receive four shell molds 400. The inner surface of the outer mold 300 in contact with the shell 400 is configured to provide a small fit for the shell 400 to avoid bursting of the walls of the shell 400 under the discharge pressure created during the injection of melt into the mold 300.

Each shell 400 is configured to form a separate lock 105. Thus, four locks 105 may be made in a single casting process. It will be appreciated that the overmold 300 may be provided in different sizes to accommodate different numbers of shell molds 400, thereby facilitating the casting of different numbers of locks 105 in a given casting sequence.

In the illustrated embodiment, four sets of vent openings 325 and 330 are provided in the cope portion 305 of the mold to vent gases from the four shell molds 400. Vent openings 325 and 330 are generally disposed over vent openings 405 and 410, respectively, of the shell 400.

The first set of vent openings 330 are positioned on a first set of vent openings 410 of the shell 400 adjacent to a location of the shell 400 corresponding to a first end of the lock (e.g., the rear leading end 205). The second vent opening 325 is positioned in the second vent opening 405 of the shell 400 at a location of the shell 400 corresponding to the second end of the lock (e.g., the knuckle side end 215). Side vent holes disposed adjacent to corresponding side vent holes 335 (fig. 3) formed in the shell mold 400 are formed in the drag portion 307 of the overmold 307.

Vent openings 330 and 325 in the overmold cope section 305 extend from the exterior surface of the cope section 305 (see fig. 3) to the interior surface of the cope section 305 (see fig. 4 a). The alignment of the various vent openings 330, 325, 405, and 410 is critical to complete removal of the gases generated during the casting process. The vent openings 325 and 330 of the overmold cope portion 305 may be placed within the recess 422 to relax the positioning restrictions of the vent openings 330, 325, 405, and 410. The pockets 422 are sized to ensure that gases are vented through the vent openings 405 and 410 of the shell 400 and that other gases remain within the pockets 422. That is, the recess 422 is sized to accommodate variations in the relative positioning between the vent openings 325 and 330 of the overmold cope portion 305 and the vent openings 405 and 410 of the shell 405. For example, the recess 422 is about 1 inch wide and about 2 inches long. The depth of the recess 422 is about 0.125 inches. It is understood that recesses may also be formed in the shell 400 to achieve the same effect.

The positioning of vent holes 405 and 410 at both ends of lock 105 helps ensure that all gas within shell 400 has an escape path. This results in a stronger lock 105 with fewer surface imperfections since the gas does not penetrate into the casting, and the gas may additionally constitute bubbles that make the lock 105 weaker. The location of the vent holes 405 and 410 also helps ensure that the thicker upper section of the lock 105 (i.e., the rear leading end 205) and the thinner lower section of the lock 105 (i.e., the knuckle side end 215) remain stable and do not deform or change dimensions such that the two lock sections differ significantly in volume.

As shown in fig. 4a, a pair of risers 415 are molded into the cope portion 305 of the overmold 300 and a gating system 420 is molded into the drag portion 307 of the overmold 300. During casting, the melt flows through the down sprue 320 into the overmold 300, through the gating system 420, into the riser 415, and finally into the shell 400 through a gate 505 (fig. 5) connecting the shell 400 and the gating system 420. As previously noted, the riser 415 is a cavity that is filled with melt during the pouring process. As the melt in the other parts of the casting cools, the melt will flow from the riser 415 into the casting. This in turn helps to avoid the development of cracks in the casting in areas that cool more slowly than other areas therein.

Fig. 5 illustrates an interior view of the outer mold 300 after the melt is poured and solidified to form a casting. In the exemplary embodiment, the casting includes four locks 105, a sprue 505, a gating system 420, a riser 415, and a down-runner 320. The gates 505 leading to the individual locks are sized to facilitate separation of the locks 105 from the casting by tapping or other forms of impact. In this regard, gate 505 may have a diameter of between approximately 0.5 inches and 2 inches. To minimize post-separation machining, gate 505 is advantageously positioned on end surface 207 (FIG. 2 a) of back lead end 205, which is a less important part of lock 105. After the lock 105 is disengaged, the remainder of the casting (i.e., the gating system, risers, and down runners) may be melted and used in a subsequent casting process.

Figure 6a illustrates a side view of the shell 400 corresponding to the shell 400 described above. Figure 6b illustrates the cope portion 605 and the drag portion 610 of the shell 400. Cope portion 605 and drag portion 610 may be joined by an adhesive to form shell 400. For example, an adhesive may be used to adhere the various portions together.

The shell mold 400 is constructed by the so-called shell (hence the name shell mold) or hot box process, in which resin sand or a sand/resin mixture is blown into a hot metal mold by air pressure, forming a hardened shell over a period of time. The sand may correspond to fine silica sand mixed with thermosetting phenolic resin. For example, the grit fineness index of silicon may be in the range of 60-70 grit fineness indexes. The mold may be constructed of cast iron and then heated to between 230 c and 315 c until the sand in the mold hardens to a suitable depth. I.e. until the shell has the desired wall thickness. The shell is then removed from the mold and most of the unhardened sand mixture within the shell is removed. The removed sand may be used in a subsequent shell casting process after the reclamation process.

The cope 605 and drag 610 portions of the shell 400 are formed by different patterns. The shell casting technique provides high dimensional stability. Each mold defines a portion of connecting opening 607 in each portion through which melt flows into shell mold 400. The pattern defining the cope section 605 may correspond to a generally rectangular box having an open side into which sand is poured. The sidewalls of the box may be tapered to facilitate removal of the hardened cope-flask portion 605 from the box. The cope portion of the lock 105 may be molded in the bottom side of the box. Additionally, a mold may be provided to form the protrusion 620 in the cope portion 605. The protrusion 620 forms a recess 220 (fig. 2 a) in the lock. In other words, the formation of the groove 220 does not require the use of a core that is typically removed during casting. Therefore, the dimensional accuracy of the groove 220 is improved as compared with a groove formed by a core back. This in turn eliminates the machining process required to form the grooves produced by known casting processes, reducing cost.

The mold defining the drag portion 610 may correspond to a general closed box having a relatively small opening formed at one side. In typical embodiments, the opening is formed on the side of the box that defines the knuckle side end 215 of the lock 105. Sand is blown into the box through the opening and hardened as described above. The unhardened sand is removed through a small opening, leaving the vented cavity 710 (fig. 7 b).

Fig. 7a illustrates the drag portion 610 after it has been removed from the mold. As a result of the shell casting process, a residual build-up 705 of sand may form on the sides of the drag portion 605, closest to the knuckle side end 215. Excess unhardened sand is emptied from the drag portion 610 through an opening 335 formed inside the accumulation 705. As shown in fig. 3, the opening 335 in the inside of the drag portion corresponds to the opening 335 in the side of the overmold 300. Removal of the excess sand exposes a vented cavity 710 in the drag portion 605, as illustrated by section 712 a-a' of the drag portion 605 shown in fig. 7 b.

As shown in fig. 8, the pattern for the drag portion 605 of the shell 400 is arranged such that the vent cavity 710 (dashed line) generally follows the shape of the leg portion 210 of the lock 105. That is, the vented cavity 710 is along a significant portion of the lock 105. This allows gases formed during casting to escape into the vent cavity 710 and out through the vent opening 335 without entering the casting, which, as noted above, could otherwise result in additional bubbles in the casting causing the casting to be weak or surface flaws requiring repair. This form of vent further improves the dimensional accuracy of the lock 105.

Returning to FIG. 6a, as the parting line 615 separating the drag portion 610 from the cope portion 605 travels from the rear lead end 205 segment down through the pillar portion 210 and to the knuckle side end 215, it constitutes a non-linear path along the natural shape of the profile of the lock 105. The non-linear path facilitates self-alignment of the cope and drag portions 605 and 610 of the shell 400 and results in a parting line 615 of the lock 105 that substantially follows the non-linear profile of the lock 105.

FIG. 9 is a block diagram of a process performed in manufacturing the lock 105 as described above. At block 900, cope and drag portions 605 and 610 of the shell 400 for the cast lock 105 are formed. Each section may be made of fine silica sand covered with a thermosetting phenolic resin coating. Sand is loaded into individual boxes defining cope and drag molds and heated until a shell of the desired thickness is obtained. Excess sand is removed from the drag portion 610 of the shell mold 400 to expose the vent cavities 710, the vent cavities 710 facilitating venting of gases from the drag portion 610 during casting. The cope and drag portions 605 and 610 are attached to each other by an adhesive. The non-linear parting line 615 separating the cope and drag sections 605 and 610 facilitates easy alignment of the sections.

In block 905, the cope and drag portions 305 and 307 of the overmold 300 are formed. The cope and drag portions 305 and 307 are made of relatively inexpensive materials such as naturally hardened or self-hardening sand materials. Reclaimed sand from a previous casting process may be used for portions of the outer mold 300. The interior of the overmold 300 is shaped to receive the shell 400 and provide a close fit for the shell 400, thereby supporting the walls of the shell 400 during casting.

The gating system 420 and one or more risers 415 may be molded within the interior of the overmold 300. Runner system 420 is coupled to each shell 400 through gate 505. Gate 505 is sized to facilitate separation of lock 105 from the casting by tapping or other forms of impact.

At block 910, the shell 400 is inserted into the overmold 300. In block 912, the overmold is assembled. Next, in block 915, the melt is injected into the down sprue 320 of the overmold 300. The melt may be steel or other suitable material. The melt flows down the down sprue 320, through the gating system 420, and into the shell 400 through the connection 505. Air or other gases that would otherwise be trapped in the shell 400 escape through the vent openings 405 and 410 defined in the cope portion 605 of the shell 400 and subsequently escape through the vent openings 325 and 330 defined in the cope portion 305 of the overmold 300. The vent openings 325 and 330 in the overmold 300 are generally disposed above the vent openings 405 and 410 of the shell 400. Other gases escape from shell 400 through the cavity formed in drag portion 605 of shell 400. These gases exit through openings 335 in the side of the drag portion 605 of the shell 400 and are eventually vented to the atmosphere through openings in the side of the overmold 300.

In block 920, the hardened casting is removed from the mold 300. For example, the mold 300 may be split to expose the casting. The used sand may be decomposed and regenerated to form a subsequent mold.

In block 925, the lock 105 and the casting are separated. For example, an impact hammer may be used to separate the gating system 420 and the connector 505 from the lock 105.

At block 930, the lock 105 is machined. For example, end face 207 of lock 105, where connector 505 is formed, may be ground to a relatively smooth finish. All remaining material of the runner system may be ground flat. The remainder of the lock 105 may then be sandblasted to a smooth finish. After blasting, the lock 105 is ready for operational use. That is, the lock 105 is ready to be inserted into the coupler body 100 without further machining.

As previously described, the exemplary embodiment for making a lock facilitates manufacturing a lock 105 that requires minimal machining. For example, a shell mold 400 made of fine silica sand is used to define the lock casting. The shell 400 is supported by a relatively inexpensive overmold made of a naturally-hardening or self-hardening sand material. Various locks can be produced in the outer mould by means of suitable shell moulds. A gating system and risers are formed in the outer mold to distribute the melt to the individual shell molds. The vent holes formed in each mold allow gas to escape, thereby improving the dimensional accuracy of the lock.

Although different embodiments of the embodiments have been described, it is obvious to a person skilled in the art that further embodiments and embodiments are possible within the scope of the claims. The various dimensions described above are merely exemplary and can be varied as desired. Accordingly, it will be apparent to one skilled in the art that many more embodiments and implementations are possible within the scope of the claims. Therefore, the above-described embodiments are provided only to assist understanding of the claims and do not limit the scope of protection of the claims.

Claims (36)

1. A method for manufacturing a lock for a railcar coupler, wherein the lock has a rear guide portion at a first end, a leg portion at a mid-section, and a recess at a second end, wherein a knuckle side surface of the lock adjacent the first end defines a knuckle locking face and a coupler side surface of the lock opposite the knuckle side surface defines a coupler locking face, the method comprising the steps of:

forming a mold of a lock in a drag portion and a cope portion of a first mold comprising a first molding material, thereby forming a cavity defining an outer surface of the lock;

forming a cavity having an interior surface substantially complementary to an exterior surface of the first mold in a second mold comprising a second molding material;

forming a runner, a gating system in fluid communication with the runner, a riser in fluid communication with the gating system, and a sprue in fluid communication with the gating system and the first mold in the second mold;

curing the first and second casting molds;

combining a drag portion and a cope portion of the first mold;

inserting the first casting mold into the second casting mold;

combining the drag portion and the cope portion of the second mold; and

injecting a melt into a down-runner of the second casting mold, wherein the melt subsequently flows into the first casting mold to form the lock.

2. The method of claim 1, further comprising inserting the first mold into a cavity of the second mold.

3. The method according to claim 1, wherein the first mold is a shell mold having a gate, and wherein during forming the first mold, uncured first molding material is removed from the first mold through a vent opening defined on a side of at least one of a drag portion and a cope portion of the first mold, thereby exposing a vent cavity in the at least one portion, wherein the vent cavity is not connected to a cavity defining an outer surface of the lock.

4. The method of claim 1, wherein the outer wall of the first mold is tapered.

5. The method according to claim 1, wherein a parting line of the first mold separating the cope portion from the drag portion follows a non-linear profile of the lock.

6. The method of claim 1, wherein the first modeling material is a mixture of silica sand and a thermosetting phenolic resin.

7. The method of claim 6, wherein the second modeling material is a naturally hardening material.

8. The method of claim 7, wherein the second modeling material includes a first layer of mechanically separated sand that forms an exterior of the mold, and further including a second layer of mechanically and thermally separated sand that forms an interior of the second mold that will contact the first mold.

9. The method of claim 1, wherein the first modeling material and the second modeling material are the same material.

10. The method of claim 1, wherein a tolerance of a distance between a generated knuckle locking face and a generated coupler locking face of the generated lock is about less than or equal to ± 0.010 inches immediately after removing the lock from the first mold.

11. The method according to claim 1, wherein at least one of the cope and drag portions of the first mold defines a protrusion that forms the groove.

12. The method of claim 1, wherein an interior of the drag portion of the second mold is configured to receive at least two shell molds and to distribute melt to each of the at least two shell molds.

13. The method of claim 1, wherein a gate to the lock formed during casting is provided to be separated.

14. The method of claim 13, wherein the diameter of the gate is less than 2 inches.

15. The method of claim 13, wherein the gate to the lock is located on top of the first end of the lock.

16. A method for manufacturing a lock for a railcar coupler, wherein the lock has a rear guide portion at a first end, a leg portion at a mid-section, and a recess at a second end, wherein a knuckle side surface of the lock adjacent the first end defines a knuckle locking face and a coupler side surface of the lock opposite the knuckle side surface defines a coupler locking face, the method comprising the steps of:

forming a mold of a lock in a drag portion and a cope portion of a first mold comprising a first molding material, thereby forming a cavity defining an outer surface of the lock, wherein the cope portion defines a first opening for venting gas;

forming a cavity having an interior surface substantially complementary to an exterior surface of the first mold in a second mold comprising a second molding material;

forming a first opening in the cope portion of the second mold configured to vent gas vented from the first opening in the cope portion of the first mold;

forming a runner, a gating system in fluid communication with the runner, and a gate in fluid communication with the gating system and the first mold in the second mold;

curing the first and second casting molds;

combining a drag portion and a cope portion of the first mold;

inserting the first casting mold into the second casting mold;

combining the drag portion and the cope portion of the second mold; and

injecting a melt into a down-runner of the second casting mold, wherein the melt subsequently flows into the first casting mold through the gating system and the gate to form the lock, wherein gas in the first casting mold is extruded by the melt through the first opening in the cope portion of the first casting mold and subsequently through the first opening in the cope portion of the second casting mold.

17. The method according to claim 16, wherein the cope portion of the first mold defines a second opening for venting gas, wherein the first opening in the cope portion of the first mold is disposed proximate the first end of the lock and the second opening in the cope portion of the first mold is disposed proximate the second end of the lock.

18. The method according to claim 17, wherein the first opening is provided at a location of the lock closest to a top surface of a cope portion of a drag mold.

19. The method according to claim 16, wherein the cope portion of the second mold defines a second opening configured to vent gas vented from the second opening of the cope portion of the first mold.

20. The method of claim 16, wherein the cope portion of the second mold defines a recess surrounding the first opening in the cope portion of the second mold, and the recess is about 1 inch wide and about 2 inches long.

21. The method of claim 20, wherein the recess is greater than about 0.125 inches deep.

22. The method according to claim 16, wherein the cope portion of the first mold defines a vent cavity positioned substantially adjacent an area of the cope portion forming the pillar portion of the lock, wherein the vent cavity does not receive melt during casting and is configured to vent gas through an opening formed on a side of the cope portion of the first mold and through a side opening formed in the second mold.

23. The method of claim 16, wherein a tolerance of a distance between upper and lower lock faces of the lock is about less than or equal to ± 0.020 inches immediately after removing the lock from the first mold.

24. A method for manufacturing a lock for a railcar coupler, wherein the lock has a rear guide portion at a first end, a leg portion at a mid-section, and a knuckle side defining a recess at a second end, wherein a knuckle side surface of the lock adjacent the first end defines a knuckle locking face and a coupler side surface of the lock opposite the knuckle side surface defines a coupler locking face, the method comprising the steps of:

forming molds for at least two locks in a drag portion and a cope portion of a mold containing a naturally hardened molding material, thereby forming cavities defining outer surfaces of the at least two locks;

forming a down sprue, a runner system in fluid communication with the down sprue, and at least two gates each in fluid communication with the runner system and one of the at least two cavities from a naturally hardening molding material;

hardening the naturally hardened molding material;

combining the drag and cope portions of the mold; and

injecting the melt into the hardened naturally hardened molding material down-runner, wherein the melt then flows through the gating system and into the mold cavity, thereby forming the at least two locks.

25. A casting assembly for manufacturing a lock of a railcar coupler, wherein the lock has a rear guide portion at a first end, a leg portion at a mid-section, and a groove at a second end, wherein a knuckle side surface of the lock adjacent the first end defines a knuckle locking face and a coupler side surface of the lock opposite the knuckle side surface defines a coupler locking face, the casting assembly comprising:

a drag portion and a cope portion of a first mold defining an outer surface of the lock, wherein the first mold comprises a first molding material;

a second mold made of a second molding material, the second mold defining a cavity having an interior surface substantially complementary to an exterior surface of the first mold;

a down-runner formed in the second mold;

a gating system formed in the second casting mold in fluid communication with the down sprue;

a gate formed in the second mold in fluid communication with the gating system and the first mold.

26. The casting assembly according to claim 25, wherein the first mold is a shell mold.

27. The casting assembly according to claim 25, wherein a parting line of the first mold that separates the cope portion from the drag portion follows a non-linear profile of the lock.

28. The casting assembly according to claim 25, wherein the first molding material is a mixture of coated silica sand and a thermosetting phenolic resin.

29. The casting assembly according to claim 27, wherein the second molding material is a naturally hardening material.

30. The casting assembly according to claim 25, wherein the first molding material and the second molding material are the same material.

31. The casting assembly according to claim 25, wherein at least one of the cope and drag portions of the first mold defines a protrusion that forms the groove.

32. The casting assembly according to claim 25, wherein an interior of the drag portion of the second mold is configured to receive at least two shell molds and to distribute melt to each of the at least two shell molds.

33. The casting assembly according to claim 25, wherein a gate to the lock formed during casting is provided to be separated.

34. The casting assembly according to claim 33, wherein the gate has a diameter of less than about 2 inches.

35. The method of claim 33, wherein the gate to the lock is located on top of the first end.

36. A method for manufacturing a lock for a railcar coupler, wherein the lock has a rear guide portion at a first end, a leg portion at a mid-section, and a recess at a second end, wherein a knuckle side surface of the lock adjacent the first end defines a knuckle locking face and a coupler side surface of the lock opposite the knuckle side surface defines a coupler locking face, the method comprising the steps of:

forming a mold of a lock in a drag portion and a cope portion of a first mold comprising a first molding material, thereby forming a cavity defining an outer surface of the lock;

forming a cavity having an interior surface substantially complementary to an exterior surface of the first mold in a second mold comprising a second molding material; and

a down runner, a gating system in fluid communication with the down runner, a riser in fluid communication with the gating system, and a gate in fluid communication with the gating system and the first mold are formed in the second mold.